1. Field of the Invention
This invention relates generally to the fluid handling art and more particularly to an improved sound suppressing fluid handling device, such as a valve, for conducting a pressurized fluid relatively noiselessly through a substantial pressure drop.
2. Prior Art
Many fluid handling applications involve transmission of a pressurized fluid through a substantial pressure drop. This pressure drop normally occurs through valves of one kind or another but it may occur another way. In any event, unless preventative steps are taken, substantial noise is generated by the fluid as it undergoes the pressure drop due to cavitation and other causes. Reduction or elimination of this noise is often desirable or mandatory, depending on the nature of the fluid handling application.
A variety of mufflers and other sound suppressing fluid handling devices have been devised for this purpose. U.S. Pat. No. 3,917,222, for example, discloses a fluid suppressing flow control valve.
Generally speaking, such sound suppressing fluid handling devices attenuate sound by controlled dissipation of the fluid energy as the fluid undergoes its pressure drop. This energy dissipation is commonly accomplished by passage of the fluid through a myriad of tortuous passages formed within a sound suppressing device of some kind. In the above mentioned patent, for example, this sound suppressing device comprises a stack of annular discs with faces which are chemically etched or machined to form the energy dissipating passages between the discs. The particular valve described in this patent is designed for use with liquid or gas, and its sound suppressing or energy dissipating passages are designed to perform the additional function of achieving relatively constant velocity flow through the valve.
The design and fabrication of sound suppressing fluid handling devices of this kind presents three related problems with which this invention is concerned. These problems involve (a) maximizing the number and length of the fluid energy dissipating or sound suppressing fluid passages per unit volume so as to provide an effective sound suppressing fluid handling device of minimum overall size and yet possessing the desired flow capacity, (b) forming or fabricating the passages in a practical manner, adaptable, for example, to mass production techniques, and (c) packaging the sound suppressing means in a manner which is practical from a manufacturing standpoint and utilizes the sound suppressing function with maximum efficiency.